Originally Posted by
Rowan
Step well away form the idea that you could fit disc brakes to the back of that bike, niko. The bike is not designed for them, at all. The other posters are correct -- they are holes that have been tapped to take bolts that hold on a rack and mudguard as optional extras.
The problem is that the holes are much further apart than most rack mounts would be. They are also 22 mm apart which just happens to be the spacing for one of the obsolete brake mount adapters. I doubt you can find the proper mount anymore so I is likely a moot point but I wouldn't be so sure to call this a rack/fender mount. We need so more information.